Apparatus for slant hole directional drilling

ABSTRACT

Method of slant hole directional drilling using a rotary drill wherein the drill collar carrying a plural cone bit is nudged upwardly on each revolution by a radially projecting lobe being cam bearing on the surface at the low side of the hole, in conjunction with the action of one oversize cone in the bit which upon each upward nudging of the drill collar cuts in a predetermined laterally angular direction, whereby the direction of the well bore will be altered. The apparatus embodies a two cone or tricone bit in which the teeth of one cone are radially enlarged over the teeth of the other cone or cones, the bit bein mounted on a drill collar with the larger cone at an angular displacement from a radially projecting lobe or cam mounted on the drill collar.

United States Paten 11 1 McMahon I 111 3,825,081 [451 July 23,1974

[ APPARATUS FOR SLANT IIOLE DIRECTIONAL DRILLING [76] Inventor: Harvey S. McMahon, 4661 Rhapsody Dr., Huntington Beach,

Calif. 92649 t 122] Filed: Mar. 8, 1973 [21] Appl. No: 339,321

[52'] US. Cl. 175/73, 175/325 [51] Int. Cl E2lb 7/08 [581 Field of Search 175/61, 73, 76, 325, 343, 175/376 [56] References Cited UNITED STATES PATENTS 2,734,720 2/1956 Zublin 175/76 2,819,040 1/1958 James et al. 175/325 X 2,876,992 3/1959 Lindsay 175/73 3,045,767 7/1962 Klassen 175/325 X 3,081,829 3/1963. Williams 175/376' 3,092,188 6/1963 Farris et al 175/76 3,154,156 10/1964 Moore et al. 175/76 3,306,378 2/1967 Williams 175/325 11/1967 Livingston 175/73 2/1969 Bennett 175/343 ABSTRACT Method of slant hole directional drilling using a rotary drill wherein the drill collar carrying a plural cone bit v is nudged upwardly on each revolution by a radially projecting lobe being cam bearing on the surface at the low side of the hole, in conjunction with the action of one oversize cone in the bit which upon each upward nudging of the drill collar cuts in a predetermined laterally angular direction, whereby the direction of the well bore will be altered.

Theapparatus embodies a two cone or tricone bit in which the teeth of one cone are radially enlarged over e h of the he QUQPPQPUfi; he bitb mounted on a drill collar with the larger cone at an angular displacement from a radially projecting lobe .or cam mounted on the drill collar.

5 Claims, 7 Drawing Figures 21 LJ m E wr 25 g T j E 9 Z 4 f3 2:3 35% H f g {/i a 3 V n r. I" 7 APPARATUS FOR SLANT HOLE DIRECTIONAL DRILLING BACKGROUND on THE INVENTION reason or another is unsuitable for a continuation of straight drilling. Sometimes it is done as a relief well for uncappable blowouts, or to control fires. In some cases, it is highly desirable to control both the horizontal and vertical deviation within predetermined limits.

Various primary deflection tools have been employed for initiating and maintaining'the desired hole direction. Some are limited to the vertical angle only. Some such as whipstocks, and knuckle joints, are difficult to control. A more recent development comprises a fluid actuatedadjustable sub which suspends a bottomhole fluid-driven bit from a well string. Another known tool involves paddlesinterconnected by a shaft which is externally mounted in a groove on a drill collar.

These, and other systems known to applicant are unsatisfactory in many respects from the standpoint of malfunctions, added cost in equipment and in operation and maintenance, and lack of adequate control.

SUMMARY OF THE INVENTION The present invention is exemplified in both a method and an apparatus.

A principal object is to provide a method for slant hole directional drilling which is relatively simple to practice, and which lends itself to more accurate control than prior methods known to applicant.

One step is to impart an upward thrust of the bit end of the drill collar with sufficient frequency to produce the cumulative effect of pointing the bit somewhat upwardly. Concurrently with each upward thrust the bit is caused to attack an area laterally offset from the cylindrical plane of the hole immediately preceding the area of attack. The compositeresult is a bending of the hole to one side or the other, and/or to some extent upwardly. The attack of the bit can be arranged to proceed to either side, or upwardly without deviation to either side. The action can be made effective over a circular section described generally as extending from 8 a two cone) roller bit mounted at the lower end of a drill collar, the collar being'provided with a lobe or cam or other radial projection spaced upwardly from the bit, and one cone of the bit being formed with a buildup (extensions) of the teeth resulting in a larger cone diameter than that of the other cone or cones.

vIf the specially formed bit is disposed in a plane diametrically opposite the cam, only vertical deflection is achieved. By disposing such bit in a plane circumferentially (angularly) offset from the diametric plane of the cam, deflection is obtained primarily either to the right or left from the axis of the preceding section of the bore.

As the drill collar is rotated, the bit makes an oversize" hole. Assuming that slant drilling is in process, with each revolution of the collar, the cam rides on the bottom'of the hole; This imparts an upward thrust which nudges the bit end of the collar upwardly, and, if the'oversize cone is circumferentially offset from the blade, the path it cuts deviates laterally or vertically,

that is, left or right, or upwardly, according to the angular offset of cam and oversize cone.

The degree of deviation is responsive to several factors: the axiallocation of the cam on the collar, the dimension of its radial projection, and the dimension of the oversize cone relative'to the other cone or cones.

' The arc of the bore is thus primarily determined; and

tors mentioned.

The cam'may be specifically designed, or it may be a blade or stabilizer of the type which conventionally is mounted in a series of three, equally spaced around the circumference of a drill collar to center the collar in drilling a straight hole. Eliminating all but one of these, in combination with the oversize cone, enables me to achieve the different and special function needed.

The roller bit may be a standard tricone or two cone type bit designed forwhatever formation is to be penetrated, with a buildup of the teeth on one cone, or in originally manufacturing the bit one larger cone may be installed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat diagrammatic section of a well the arc may be varied by changing one or all of the facbore with the tool shown working therein.

FIG. 2 is a vertical sectional view of a first form of the tool, shown in the well bore.

FIG. 3 is an enlarged section taken on the line 33 I FIG. 5, showing the oversize cone positioned relative to the cam or lobe for right hand deviation.

FIG. 7 is a view similar to FIG. 6 showing the oversize cone positioned for left hand deviation.

FIRST EMBODIMENT OF THE INVENTION In FIG. 1, the bracketed section S illustrates a straight slant well bore drilled down from the surface 15..The bracketed section T illustrates my special tool in the bore ready to start a deflection. The lower section D in broken lines indicates the angular deflection path to be followed in proceeding with operation of the tool.

. The drilling tool generally designated 20, is coupled steel hollow tube with threads at its upper end for connection with the drill string, and a threaded box 26 at its lower end which receives the shank 27 of a bit 28.

The mandrel is formed with a reduced diameter section 30 commencing at an annular shoulder 31 whereby a sleeve 32 may be fitted over the reduced section. The upper end 33 of the sleeve is adapted to abut the shoulder 31, and the lower end 35 is adapted to seat on an annular ledge 36 of the shank 27. v

The mandrel 23 and the sleeve 32, when assembled, comprise the drill collar 22.

Intermediate the ends of the drill collar'is fixedly mounted a cam or lobe 38. This may be similar to stabilizers which conventionally are spaced evenly around the periphery of a drill collar to maintain the collar concentrically within the bore for drilling straight holes. The omission of all but one such stabilizer is for an entirely'different purpose resulting in a different function, as previously mentioned and as will be-developed further in this description.

In the preferred form I use a true cam shape, as shown in FIG. 3', welded on the surface of the sleeve 32. The placement of the cam is determined by reference to the radial or angular disposition of an enlarged cone 40 on the bit 28 which will be further described. I

This bit 28 is conventional in some respects. .A tricone type is illustrated. It comprises the shank 27 already identified, formed with the annular ledge or shoulder 36, and bit legs 41. On these legs are rotation:- ally mounted cones 40, 46 and 47 embodying teeth 48, 49 and 50. The size and placement of teeth 49 and 50 are such as found in astandard tricone bit. Their extremities lie in a circular plane representing the approximate circumference of a bore which would be cut by a standard tricone bit of this type.

The departure from the conventional, which is an important part of my invention, lies in the buildup, or enlargement of the teeth 48 on the cone 40. As an example by way of illustration and not of limitation, if the teeth on the cones 46 and 47 are designed to cut a 9 5/8 inch bore, the teeth on cone 40 extend approximately 1/4 inch beyond. See FIG. 3.

This can be accomplished in the manufacture of the cone, or the teeth of a 9 5/8 inch cone may be built up an additional 1/4 inch by adding metal through a process comparable to welding. v

Provision is made to orient the cam relative to the oversize cone. This is achieved by lugs 52 welded to the external surface of the bit legs 41. A selected one of the lugs keys between a selected pair of stops 53 which are welded on the lower end of the sleeve. The lugs may be spaced 90 to 120 apart, and the pairs of stops similarly. It is preferable that the pairs of stops on the sleeve be circumferentially disposed approximately 90 to 120 from the peak of the cam..

In assembling the tool the bit may be placed on a table, the mandrel is suspended above it, and the sleeve is pushed up on the mandrel. The'operator then allows the sleeve to slide down and is rotated as desired so that the selected stops engage the selected lug on the bit. The mandrel is then turned totighten the threads on the shank and bring the assembly into a unitary relationship.

In its elementary form, the device needs only two pairs of stops, and two lugs. One is utilized for deviation left, and the other for deviation right. The string always turns clockwise (lookingdown). For'left hand deviation with the'peak of the cam at 6 o'clock, the oversize cone is advantageously located at approximately 9 oclock; and for right hand deviation the oversize cone would be at approximately 3 oclock. These spacings may be modified if desired.

Second Embodiment of the Invention an elongated shoe 139 preferably ,of aluminum or other relatively soft metal, capped by a sheath 140 of hard steel. These parts are made with arcuate cross sections sothat the assembly conforms to the outer surface of the drill collar; and they are secured to the collar by capscrews 141 threaded into-a selected line of a series of tapped sockets 142.

OPERATION The operation of both forms of. the invention is essentially the same.

Assuming a clockwise rotation of the drill string and the tool, as observed looking down, and working in a slant well bore, the cam during several degrees of rotary travel will contact the low side of the bore. For ex planation this will be referred to' generally as six oclock. Engagement with the low side of the bore causes a shifting of the axis of the tool upwardly.

Assume that the oversize or radially offset cone is disposed generally at nine oclock during the time the cam is at six oclock. During the upward shift of the axis of the tool the oversize cone attacks at the left side of the bore, while the minor size cone or cones advance in their own circular plane.

With continued rotation, and the cam itself rising from the low side, the tool settles by gravity and its axis lowers so that the major cone continues past 12 oclock, 3 oclock and 6 oclock without the extra radial thrust.

With each revolution the oversize cone continues its the oversize cone diametrically opposite. The latter action could be accomplished, although less efficiently,

by using a cam in association with a conventional bit (absent the oversize cone).

The angular attack of the oversize cone occurs with each revolution of the tool. Occurringwhen the blade is rotating through a relatively minor are at the low side, compared to cessation of the blade action when travelling through the relatively major are on the high side, the directional change in the bore is gradual. The cumulative effect of the cutting action is to produce a bore with a generally oval cross section, thus facilitating advance of the tool during the angular or curving operation.

While my primary purpose is to alter the direction of the well bore in accordance with a predetermined plan, the too] might be used, if desired, to correct for unwanted deviation in straight bore slant hole drilling.

Alternative Embodiments Of The Invention It shouldbe clear from the foregoing descriptions that for deviation an eccentric orbit of the cutting action is utilized. This is best accomplished by the combination of the oversize cone and the cam. It could also be achieved by offsetting a conventional bit in combination with the cam. An example would be to angle the axis of the thread couplingbetween the shank of the bit and the drill collar. Another example would be to offset the box from the axis of the collar. Still another would be to employ a bent sub between the bit and the cam.

Although I have herein shown and described my in-. vention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention.

1 claim:

1. Apparatus for slant hole directionaldrilling comprising an annular elongated drill collar, a roller bit mounted at an end of the drill collar, the bit comprising a plurality of cones, the teeth of one cone projecting radially from the axis of the drill collar a greater distance than the teeth of the other cone or cones, a single radial projection on the drill collar spaced axially above the bit, the projection and the one cone of the bit being disposed in a predetermined angular offset relationship, whereby as the drill collar is revolved in a slant hole the projection rides on the low side of the hole with each revolution thus camming the bit end of the drill collar upwardly and the one cone simultaneously cuts laterally away from the circular plane of the hole immediately preceding such lateral cutting action.

2. Apparatus as defined in claim 1 in which the drill collar comprises a mandrel and a sleeve thereon, the radial projection is mountedon the sleeve of the drill collar, stops mounted at the lower end of the sleeve, lugs provided on the bit adapted selectively to key with a stop for fixing circumferential relation of sleeve and bit, whereby offset angular relation of the one cone and the radial projection may be adjustably fixed.

3. Apparatus for slant hole drilling comprising a rotary drill collar, a cutting element mounted on the drill collar, and means on the drill collar engageable with the bottom of the hole to impart an eccentric motion to the cutting element during its rotation, the means to impart the eccentric motion comprising a cam on the drill collar,the cutting element comprising a roller bit, the roller bit including a plurality of cones, one cone being oversized relative to the other cone or cones, and the oversized cone being disposed circumferentially offset relative to the position of the cam.

4. Apparatus for slant hole directional drilling comprising a rotary drill collar, a roller bit mounted on the drill collar, nudging means fixedly mountedon the drill collar protruding radially therefrom at one circumferential location only engageable with the bottom of the hole on each revolution to impart a deviation in the direction of attack of the roller bit duringthe engagement of said means with the bottom of the hole, said roller bit comprising teeth which at a circumferential spacing from said nudging means extend a greater radial distance from the axis of the drill collar than they extend at the circumferential location of said means.

5. Apparatus for slant hole directional drilling comprising an annular elongated drill collar, a roller bit mounted at an end of the drill collar, the bit comprising teeth extending radially from the axis of the drill collar a greater distance in one direction than in the diametrically opposite direction, a single radial projection on the drill collar spaced axially above the bit, the single projection and the extending teeth of the bit being disposed in 'a predetermined angular offset relationship, whereby as the drill collar is revolved in a slant hole the projection rides on the low side of the hole with each revolution thus camming the bit end of the drill collar upwardly and the extending teeth simultaneously cut laterally away from the circular plane of the hole immediately preceding such lateral cutting action. 

1. Apparatus for slant hole directional drilling comprising an annular elongated drill collar, a roller bit mounted at an end of the drill collar, the bit comprising a plurality of cones, the teeth of one cone projecting radially from the axis of the drill collar a greater distance than the teeth of the other cone or cones, a single radial projection on the drill collar spaced axially above the bit, the projection and the one cone of the bit being disposed in a predetermined angular offset relationship, whereby as the drill collar is revolved in a slant hole the projection rides on the low side of the hole with each revolution thus camming the bit end of the drill collar upwardly and the one cone simultaneously cuts laterally away from the circular plane of the hole immediately preceding such lateral cutting action.
 2. Apparatus as defined in claim 1 in which the drill collar comprises a mandrel and a sleeve thereon, the radial projection is mounted on the sleeve of the drill collar, stops mounted at the lower end of the sleeve, lugs provided on the bit adapted selectively to key with a stop for fixing circumferential relation of sleeve and bit, whereby offset angular relation of the one cone and the radial projection may be adjustably fixed.
 3. Apparatus for slant hole drilling comprising a rotary drill collar, a cutting element mounted on the drill collar, and means on the drill collar engageable with the bottom of the hole to impart an eccentric motion to the cutting element during its rotation, the means to impart the eccentric motion comprising a cam on the drill collar, the cutting element comprising a roller bit, the roller bit including a plurality of cones, one cone being oversized relative to the other cone or cones, and the oversized cone being disposed circumferentially offset relative to the position of the cam.
 4. Apparatus for slant hole directional drilling comprising a rotary drill collar, a roller bit mounted on the drill collar, nudging means fixedly mounted on the drill collar protruding radially therefrom at one circumferential location only engageable with the bottom of the hole on each revolution to impart a deviation in the direction of attack of the roller bit during the engagement of said means with the bottom of the hole, said roller bit comprising teeth which at a circumferential spacing from said nudging means extend a greater radial distance from the axis of the drill collar than they extend at the circumferential location of said means.
 5. Apparatus for slant hole directional drilling comprising an annular elongated drill collar, a roller bit mounted at an end of the drill collar, the bit comprising teeth extending radially from the axis of the drill collar a greater distance in one direction than in the diametrically opposite direction, a single radial projection on the drill collar spaced axially above the bit, the single projection and the extending teeth of the bit being disposed in a predetermined angular offset relationship, whereby as the drill collar is revolved in a slant hole the projection rides on the low side of the hole with each revolution thus camming the bit end of the drill collar upwardly and the extending teeth simultaneously cut laterally away from the circular plane of the hole immediately preceding such lateral cutting action. 